<html>
  <head>
    <meta charset="UTF-8" />
    <title>Vue实例</title>
  </head>
  <body>
    <div id="app">{{a}}</div>
  <button onclick="test()">挂载</button>
    <script src="../lib/vue.js"></script>
    <script>
      var obj = { a: 1 }
      var vm = new Vue({
        data: obj,
      })
      function test() {
        vm.$mount('#app')
      }
    </script>
  </body>
</html>
